The 2011 short rains on Kilimanjaro summit continued until
the very end of December, with most snowfall occurring during the second half
of November. For the season, net snow accumulation on the Northern Ice Field amounted
to ~30 cm.
The image above shows an easterly view across the crater on 28
December, just prior to the year’s final snowfall event; snowcover in the
crater is often “patchier” than that on the glaciers (credit: Rohun Gholkar). On the graph, the timing of
this photograph is indicated by the light blue star. After departing the
summit, Rohun’s team encountered sleet and rain, which was likely associated
with 3 days and ~10 cm of snowfall on the glacier (see graph; dashed line
indicates midnight on New Year’s Eve).
Very little snowfall occurred during January 2012, as shown
in the lower figure, resulting in a net surface height lowering of 19 cm. Two 48-hour intervals of rapid lowering are highlighted by
red lines on the graph. Based on weather station measurements received by satellite
telemetry, these seem to have been intervals of enhanced sublimation. We cannot
be certain, but this interpretation is based on the following, which pertains
to both intervals: air temperature was
2.0 – 2.5° C lower than normal for January, the sky remained mostly clear, wind
speed was ~50% higher than normal (directly from the east), and relative
humidity averaged a very low 20-25% instead of ~60% as on a typical January
day. Together, these are perfect conditions for sublimation.
Any first-hand observations and/or photos from the summit area
during these dry intervals (Jan. 1 & 2, Jan. 22 & 23) would be greatly
appreciated!
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